49 results on '"Proust, Sébastien"'
Search Results
2. Gérer des inondations par des ouvrages dispersés sur le bassin versant : principes et méthodes de diagnostic d'efficacité probabiliste
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POULARD, Christine, ROYET, Paul, LEBLOIS, Étienne, FAURE, Jean-Baptiste, BREIL, Pascal, and PROUST, Sébastien
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Inondation ,Risque ,Bassin versant ,Ouvrages ,Méthodes ,Diagnostic ,Environmental technology. Sanitary engineering ,TD1-1066 ,Environmental sciences ,GE1-350 - Abstract
La gestion intégrée des inondations à l’échelle du bassin versant offre des perspectives intéressantes pour poser un diagnostic pertinent et trouver des solutions de gestion de l’aléa, notamment à l’amont des enjeux. Cet article s'intéresse ici aux différentes étapes de l'estimation de l'aléa inondation et nous présente les principes et méthodes de diagnostic d'efficacité probabiliste pour améliorer la gestion des inondations par des ouvrages de prévention dispersés sur le bassin versant.
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- 2017
3. Experimental and numerical study of unsteady flows in a compound open channel
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Kaddi, Yassine, Proust, Sébastien, Faure, Jean-Baptiste, and Cierco, François-Xavier
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- 2024
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4. Can the 2D shallow water equations model flow intrusion into buildings during urban floods?
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Dewals, Benjamin, Kitsikoudis, Vasileios, Angel Mejía-Morales, Miguel, Archambeau, Pierre, Mignot, Emmanuel, Proust, Sébastien, Erpicum, Sébastien, Pirotton, Michel, and Paquier, André
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- 2023
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5. New Developments in a 1D+ ISM Model for Operational Purposes
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Kaddi, Yassine, Cierco, François-Xavier, Faure, Jean-Baptiste, Proust, Sébastien, Kostianoy, Andrey, Series Editor, Carpenter, Angela, Editorial Board Member, Younos, Tamim, Editorial Board Member, Scozzari, Andrea, Editorial Board Member, Vignudelli, Stefano, Editorial Board Member, Kouraev, Alexei, Editorial Board Member, Gourbesville, Philippe, editor, and Caignaert, Guy, editor
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- 2022
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6. 'To Take Care of the Land Means Taking Care of Ourselves': Local Perceptions on Human and Environmental Health in a High Agro-Biodiversity Landscape in the Yucatan Peninsula
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Méndez-López, María Elena, Cepeda-González, María Fernanda, Rodríguez-Robayo, Karla Juliana, Juárez-Téllez, Lilian, Rivera-De Velasco, Mariana, Peralta-Blanco, Rosa Martha, Chan-Chuc, Nicolás, Serrano-Ysunza, Andrea A., Riveros-Cañas, R. Antonio, Sánchez-Siordia, Oscar G., Proust, Sebastien, Watanabe, Tsunao, Series Editor, Nishi, Maiko, editor, Subramanian, Suneetha M., editor, and Gupta, Himangana, editor
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- 2022
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7. Impact of the porosity of an urban block on the flood risk assessment: A laboratory experiment
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Mejía-Morales, Miguel Angel, Mignot, Emmanuel, Paquier, André, Sigaud, Darius, and Proust, Sébastien
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- 2021
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8. Experimental and Numerical Modelling of the Influence of Street-Block Flow Exchanges During Urban Floods
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Mejía-Morales, Miguel Angel, Proust, Sébastien, Mignot, Emmanuel, Paquier, André, Kostianoy, Andrey, Series Editor, Gourbesville, Philippe, editor, and Caignaert, Guy, editor
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- 2020
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9. New Developments in a 1D+ ISM Model for Operational Purposes
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Kaddi, Yassine, primary, Cierco, François-Xavier, additional, Faure, Jean-Baptiste, additional, and Proust, Sébastien, additional
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- 2022
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10. Experimental flows through an array of emerged or slightly submerged square cylinders over a rough bed
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Oukacine, Marina, Proust, Sébastien, Larrarte, Frédérique, and Goutal, Nicole
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- 2021
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11. Effect of climate change over landfalling hurricanes at the Yucatan Peninsula
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Appendini, Christian M., Meza-Padilla, Rafael, Abud-Russell, Said, Proust, Sébastien, Barrios, Roberto E., and Secaira-Fajardo, Fernando
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- 2019
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12. Experimental Study of Flows in a Converging Channel Followed by a Prismatic Channel with Stairs
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Chetibi, Meriem, Proust, Sébastien, Benmamar, Sâadia, Gourbesville, Philippe, editor, Cunge, Jean, editor, and Caignaert, Guy, editor
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- 2018
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13. Experimental and Numerical Modelling of the Influence of Street-Block Flow Exchanges During Urban Floods
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Mejía-Morales, Miguel Angel, primary, Proust, Sébastien, additional, Mignot, Emmanuel, additional, and Paquier, André, additional
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- 2020
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14. Laboratory Investigation Into the Effect of the Storage Capacity of a City Block on Unsteady Urban Flood Flows
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Mejía‐Morales, Miguel Angel, primary, Mignot, Emmanuel, additional, Paquier, André, additional, and Proust, Sébastien, additional
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- 2023
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15. Experimental Study of Flows in a Converging Channel Followed by a Prismatic Channel with Stairs
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Chetibi, Meriem, primary, Proust, Sébastien, additional, and Benmamar, Sâadia, additional
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- 2018
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16. DEUFI Project for Accurate Urban Flood Risk Assessment
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Paquier, André, Bader, Bruno, BERTRAND, Olivier, Dellinger, Guilhem, Dewals, Benjamin, Finaud-Guyot, Pascal, Grelot, Frédéric, Mignot, Emmanuel, Proust, Sébastien, Sop Rhee, Dong, Freddy, Vinet, RiverLy - Fonctionnement des hydrosystèmes (RiverLy), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES), Université de Liège, Littoral, Environment: MOdels and Numerics (LEMON), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut Montpelliérain Alexander Grothendieck (IMAG), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Hydrosciences Montpellier (HSM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Hydrosciences Montpellier (HSM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Gestion de l'Eau, Acteurs, Usages (UMR G-EAU), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Institut de Recherche pour le Développement (IRD)-AgroParisTech-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Laboratoire de Mecanique des Fluides et d'Acoustique (LMFA), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géographie et d'Aménagement de Montpellier (LAGAM), Université Paul-Valéry - Montpellier 3 (UPVM), and PROUST, Sébastien
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[SPI.MECA.MEFL] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] ,[SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] - Abstract
International audience
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- 2022
17. Shallow mixing layers over hydraulically smooth bottom in a tilted open channel
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Proust, Sébastien, primary, Berni, Céline, additional, and Nikora, Vladimir I., additional
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- 2022
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18. Compound channel flow with a longitudinal transition in hydraulic roughness over the floodplains
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Dupuis, Victor, Proust, Sébastien, Berni, Céline, and Paquier, André
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- 2017
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19. Mixing layer development in compound channel flows with submerged and emergent rigid vegetation over the floodplains
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Dupuis, Victor, Proust, Sébastien, Berni, Céline, and Paquier, André
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- 2017
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20. Combined effects of bed friction and emergent cylinder drag in open channel flow
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Dupuis, Victor, Proust, Sébastien, Berni, Céline, and Paquier, André
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- 2016
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21. Hydrodynamic Modeling to Characterize Floods and Predict Their Impacts
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Paquier, André, primary, Proust, Sébastien, additional, and Faure, Jean-Baptiste, additional
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- 2017
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22. List of Authors
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Beullac, Bruno, primary, Boschetti, Laurie, additional, Boudou, Martin, additional, Bravard, Jean-Paul, additional, Buffin-Bélanger, Thomas, additional, Cœur, Denis, additional, Cruz, Ana Maria, additional, Defossez, Stéphanie, additional, Demers, Sylvio, additional, Deschaux, Jocelyne, additional, Faure, Jean-Baptiste, additional, Gaume, Eric, additional, Lang, Michel, additional, Leone, Frédéric, additional, Lesbats, Michel, additional, Lhomme, Serge, additional, Carmen Llasat, Maria, additional, Lumbroso, Darren, additional, Meschinet de Richemond, Nancy, additional, Moatty, Annabelle, additional, Montané, Antonin, additional, Nussbaum, Roland, additional, Paquier, André, additional, Payrastre, Olivier, additional, Piatyszek, Eric, additional, Poulain, Daniel, additional, Proust, Sébastien, additional, Provitolo, Damienne, additional, Reghezza-Zitt, Magali, additional, Rigo, Tomeu, additional, Sauquet, Eric, additional, Serre, Damien, additional, Tardy, Alicja, additional, Tourment, Rémy, additional, Villegas, Juan José, additional, and Vinet, Freddy, additional
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- 2017
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23. Flow structure in compound open-channel flows in the presence of transverse currents
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Proust Sébastien and Nikora Vladimir
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Environmental sciences ,GE1-350 - Abstract
The structure of free-surface flows is experimentally investigated in a laboratory flume with a compound cross-section consisting of a central main channel (MC) and two adjacent floodplains (FPs). The study focuses on the effects of transverse currents on: (i) mixing layers and quasi-two-dimensional coherent structures at the interfaces between MC and FPs; (ii) secondary currents developing across the channel; and (iii) large and very-large-scale motions that were recently observed in non-compound open channel flows. Transverse currents represent spanwise depth- and time-averaged flow from MC to FPs or vice versa. The study is based on one-point and two-point ADV measurements. Streamwise non-uniform flows are generated by imposing an imbalance in the discharge distribution between MC and FPs at the flume entrance, keeping the total flow rate the same for all scenarios. It is shown that even small transverse currents can be very effective in flow modification, as they can significantly displace the mixing layer, shear-layer turbulence, and coherent structures towards MC or FP, depending on the current direction. They can also alter the distribution and strength of the secondary currents. The interactions of quasi-two-dimensional coherent structures, very-large-scale motions, and secondary currents at different conditions are also part of this study.
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- 2018
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24. Deufi project for accurate urban flood risk assessment
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Paquier, André, primary, Bader, Bruno, additional, Bertrand, Olivier, additional, Dellinger, Guilhem, additional, Dewals, Benjamin, additional, Finaud Guyot, Pascal, additional, Grelot, Frédéric, additional, Mignot, Emmanuel, additional, Proust, Sébastien, additional, Rhee, Dong Sop, additional, and Vinet, Freddy, additional
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- 2022
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25. Predicting the flow in the floodplains with evolving land occupations during extreme flood events (FlowRes ANR project)
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Proust Sébastien, Berni Céline, Boudou Martin, Chiaverini Antoine, Dupuis Victor, Faure Jean-Baptiste, Paquier André, Lang Michel, Guillen-Ludena Sebastian, Lopez Diego, Mignot Emmanuel, Rivière Nicolas, Chagot Loic, Rouzes Maxime, Moulin Frédéric, Goutal Nicole, Oukacine Marina, Peltier Yann, Ferreira Rui M.L., Brito Moisés, Alves Elsa, Gymnopoulos Miltiadis, Leal Joao, Mathurin Bastien, Soarez-Frazao Sandra, Bousmar Didier, Fernandes Joao, and Eiff Olivier
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Environmental sciences ,GE1-350 - Abstract
Flood hazards (flow depth and velocity) must be accurately assessed in high-risk areas during extreme flood events. However, the prediction of the very high flows is not an easy task due to the lack of field data and to the strong link between flow resistance and the land occupation of the floodplain. Confinement and inhomogeneity in lateral and longitudinal directions of hydraulic roughness strongly vary with return period T. The physical processes are complex, some still largely unexplored, and the assumptions linked to numerical modelling cannot be validated without field data. The FlowRes project (2015-2018), funded by the French National Research Agency (ANR), aims at improving the flood hazard assessment in floodplains in: 1) investigating in laboratory the hydrodynamic structure associated with extreme flood flows for various land occupations and flow discharge magnitudes; 2) assessing if the existing numerical modelling practices used for T ~ 100 years are still valid for extreme events with T > 1000 years, relying on the experimental data and on one field case. This paper reports some results obtained during the first year of the project.
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- 2016
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26. Large Eddy Simulation for flows through emerged or slightly sub-merged square obstacles
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Oukacine, Marina, Rtimi, Rajae, Goutal, Nicole, Larrarte, Frédérique, Loizeau, Vincent, Benhamadouche, Sofiane, Proust, Sébastien, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Sols, Roches et Ouvrages Géotechniques (GERS-SRO), Université Gustave Eiffel, Performance, Risque Industriel, Surveillance pour la Maintenance et l’Exploitation (EDF R&D PRISME), EDF R&D (EDF R&D), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and Cadic, Ifsttar
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HYDRAULICS ,OBSTACLE ,EXPERIMENTS ,SIMULATION ,[SDU.STU.HY] Sciences of the Universe [physics]/Earth Sciences/Hydrology ,FLOOD ,HYDRAULIQUE ,MODELISATION NUMERIQUE ,CRUE ,[SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology ,CFD - Abstract
River Flow 2020 -10th Conference on Fluvial Hydraulics, DELFT, PAYS-BAS, 07-/07/2020 - 10/07/2020; As a result of climate change, we believe that extreme floods will become more frequent and more intense. The flows through obstacles representing an urbanized floodplain is realised in a laboratory at Re = 4766 and 8580. The purpose of the present study is first to validate a numerical model using Large Eddy Simulation (LES) against experimental data regarding the average longitudinal velocity and the secondary vortices formation. Then, additional data can be obtained and quantified. Therefore the geometrical parameters can be changed and their influence analysed and compared to the literature. A good agreement was found between simulated and experimental vertical profiles of time averaged velocity for the flow through emerged or slightly submerged obstacles. The additional simulations highlight that the flow structure is mostly driven by the transverse aspect ratio using the distance between two adjacent obstacles.
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- 2020
27. Influence of a porous urban block on urban flood flow patterns
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Mejia Morales, M.A., Paquier, A, Proust, Sébastien, Mignot, Emmanuel, Riverly (Riverly), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire de Mecanique des Fluides et d'Acoustique (LMFA), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and ANR-18-CE01-0020,DEUFI,Détails de l'impact des inondations urbaines(2018)
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021110 strategic, defence & security studies ,010504 meteorology & atmospheric sciences ,11. Sustainability ,[SDE]Environmental Sciences ,0211 other engineering and technologies ,02 engineering and technology ,01 natural sciences ,0105 earth and related environmental sciences ,[SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] - Abstract
International audience; Urban flood laboratory experiments usually consider that the flow is mostly concentrated in streets and does not enter the building areas. However, urban blocks might modify the flow patterns at local scale due to the inflows or/and outflows through openings such as gates, windows, doors, etc. To investigate the influence of urban block porosity on flow distribution, flow depth and velocity in the surrounding streets, experiments were performed on a physical model. The results show that the urban block porosity does not substantially affect the discharge distribution in the streets located downstream of the urban block. However, flow depth, velocity and flow rate in the surrounding streets are more strongly modified.
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- 2020
28. Ondes de surface transverses dans des écoulements permanents uniformes et non-uniformes au travers d'un réseau de cylindres à base carrée émergés ou faiblement submergés
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Chetibi, Meriem, Proust, Sébastien, Benmamar, Saâdia, Ecole Nationale Polytechnique [Alger] (ENP), Hydrologie-Hydraulique (UR HHLY), and Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
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Physics::Fluid Dynamics ,relative submergence ,Non-uniform flow ,seiche ,surface wave ,vortex shedding ,open-channel flow ,[SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] - Abstract
International audience; Steady uniform and non-uniform flows through an array of emergent and slightly submerged square cylinders are experimentally investigated with a specific focus on transverse seiche waves induced by vortex shedding. The study is first and foremost aimed at assessing the effect of streamwise flow non-uniformity on seiche waves. Its secondary purpose is to investigate the change in seiche magnitude, when initially emerged cylinders become slightly submerged. Thirdly and lastly, the effect of seiche waves on mean velocities and velocity fluctuations is quantified. The lock-in process between waves and vortex shedding is unaltered by flow non-uniformity and by a change from cylinder emergence to submergence. For non-uniform flows, this results in the coexistence of two differently oscillating transverse waves close to each other. Relative wave amplitude is found to be mainly influenced by relative submergence in the case of submerged cylinders, and by Froude number and oscillation mode in the case of emergent cylinders. Finally, seiche waves modify the streamwise mean velocity, when cylinders are emergent.
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- 2020
29. Compound open-channel flows: effects of transverse currents on the flow structure
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Proust, Sébastien, Nikora, V.I., RiverLy (UR Riverly), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), UNIVERSITY OF ABERDEEN GBR, Partenaires IRSTEA, and Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
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Physics::Fluid Dynamics ,HHLAB ,SHALLOW WATER FLOWS ,[SDE]Environmental Sciences ,RIVER DYNAMICS ,SHEAR LAYER TURBULENCE - Abstract
International audience; The structure of free-surface flows in a straight compound channel was investigated in a laboratory flume, consisting of a central smooth-bed main channel (MC) and two adjacent rough-surface floodplains (FPs). The experiments covered both uniform and non-uniform flow conditions, with the latter generated by imposing an imbalance in the discharge distribution between MC and FPs at the flume entrance. The non-uniform cases involved transverse currents directed from MC to FPs and vice versa. The focus of the study was on assessing the effects of transverse currents on: (i) transverse shear layer and horizontal Kelvin-Helmholtz-type coherent structures (KHCSs) forming at the interfaces between MC and FPs; (ii) helical secondary currents (SCs) developing across the channel due to topography-induced flow heterogeneity; and (iii) turbulent large- and very-large-scale motions (VLSMs). Transverse currents can entirely displace the shear layer over FP or in MC, but they do not alter the KHCSs to the same degree, resulting in a mismatch between shear layer extent and KHCS length scales. KHCSs emerge once dimensionless velocity shear exceeds a critical value above which KHCS length scales increase with the shear. Three well-established SC cells, which are induced by turbulence anisotropy, are observed in uniform flow and non-uniform flow with transverse currents towards FP. They are replaced by a single cell in the presence of a transverse mean flow towards MC. The spectral signatures of VLSMs are visible at the upstream section of the flume but they quickly disappear along the flow, being suppressed by simultaneous development of KHCSs and SCs.
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- 2020
30. Compound open-channel flows: effects of transverse currents on the flow structure
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Proust, Sébastien, primary and Nikora, Vladimir I., additional
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- 2019
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31. Influence de la structure de l'îlot urbain sur le schéma d'écoulement le long d'une rue inondée
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Mejia Morales, M.A., Proust, Sébastien, Mignot, Emilie, Paquier, André, RiverLy (UR Riverly), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Laboratoire de Mecanique des Fluides et d'Acoustique (LMFA), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)
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[SDE]Environmental Sciences ,PHYSICAL MODEL ,URBAN FLOOD ,LABORATORY EXPERIMENT - Abstract
International audience; The study of flooding in urban environments has some complexity, mainly due to the presence of buildings, among others (e.g., vehicles, street furniture, drainage system, underground transportation system). These buildings and their facilities are grouped into blocks that are normally assumed to be impervious in urban flood studies. However, water enters these blocks through different openings such as e.g., windows, doors, gates, fences, and these lateral flow exchanges between streets and blocks can locally alter the flow pattern. In order to study these exchange processes and their influence on both flow depth and velocity in the streets during flood events, experiments were conducted on a devoted physical model termed MURI (Urban Model for the study of Inundation Risk), at Irstea, Lyon-Villeurbanne, France. The present study focused on two geometric configurations, a straight street flanked by two lateral cavities, and a straight street flanked by one-side opening. These flows were also compared to a quasi-uniform flow (reference flow without openings). The experiments have shown that a detailed description of the building blocks is required if flow depths and velocities (flood hazard) has to be locally estimated.
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- 2019
32. Influence of the urban block structure on the flow pattern along a flooded street
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Mejia Morales, M.A., Proust, Sébastien, Mignot, Emilie, Paquier, André, RiverLy (UR Riverly), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Laboratoire de Mecanique des Fluides et d'Acoustique (LMFA), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)
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[SDE]Environmental Sciences ,PHYSICAL MODEL ,URBAN FLOOD ,LABORATORY EXPERIMENT - Abstract
International audience; The study of flooding in urban environments has some complexity, mainly due to the presence of buildings, among others (e.g., vehicles, street furniture, drainage system, underground transportation system). These buildings and their facilities are grouped into blocks that are normally assumed to be impervious in urban flood studies. However, water enters these blocks through different openings such as e.g., windows, doors, gates, fences, and these lateral flow exchanges between streets and blocks can locally alter the flow pattern. In order to study these exchange processes and their influence on both flow depth and velocity in the streets during flood events, experiments were conducted on a devoted physical model termed MURI (Urban Model for the study of Inundation Risk), at Irstea, Lyon-Villeurbanne, France. The present study focused on two geometric configurations, a straight street flanked by two lateral cavities, and a straight street flanked by one-side opening. These flows were also compared to a quasi-uniform flow (reference flow without openings). The experiments have shown that a detailed description of the building blocks is required if flow depths and velocities (flood hazard) has to be locally estimated.
- Published
- 2019
33. Écoulement instationnaire en lits composés : une expérience en laboratoire et un modèle 1D+
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Kaddi, Y., Proust, Sébastien, Faure, J.B., Cierco, F.X., RiverLy (UR Riverly), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), and Compagnie Nationale du Rhône (CNR)
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UNSTEADY FLOW ,COMPOUND OPEN-CHANNEL ,[SDE]Environmental Sciences ,IMPROVED ONE-DIMENSIONAL MODEL ,LABORATORY EXPERIMENT - Abstract
International audience; This paper investigates the physical and numerical modellings of unsteady overbank flows in a compound open-channel, which consists in a main channel (MC) and one adjacent floodplain (FP). The experiments were performed in an 18 m long and 2 m wide flume. Simulations using the 1D code MAGE coupled with an improved one-dimensional (denoted as 1D+) method termed ISM (Independent Subsections Method, Proust et al. 2009) are compared to the experimental data. The originality of the ISM lies in its solving of the momentum conservation equation in each of the channel sub-sections (MC and FP). The ISM explicitly models the depth-averaged Reynolds stress at the MC/FP interface, and the transverse exchanges of mass and momentum by the mean flow between MC and FP. It also accounts for the upstream discharge distribution between MC and FP. As this method has been validated only for steady non-uniform flows, the present study aims at validating it under unsteady flow conditions. Hydrographs are injected at the flume entrance in the MC and FP, with 100 runs in order to compute ensemble averages of the flow parameters. The ratio of FP discharge to total discharge equals to 7 % at baseflow and 15 % at peakflow, while the ratio of FP flow depth to MC flow depth ranges from 0.14 to 0.30. It was found that the ISM could accurately predict the temporal variations in: (i) the flow depth along the flume; (ii) the depth-averaged streamwise and transverse velocities at the MC/FP interface; and subsequently (iii) the interfacial lateral discharge per unit length.
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- 2019
34. Rapport final du projet ANR FLOWRES
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Proust, Sébastien, RiverLy (UR Riverly), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), National Recherche (appel d'offres national ou régional), irstea, and Projet ANR-14-CE03-0010
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HHLAB ,[SDE]Environmental Sciences - Abstract
According to the European Flood Directive 2007, the flood hazard must be accurately assessed in high-risk areas over the river floodplains, during extreme flood events. However, the prediction of the very high flows is not an easy task due to the lack of field data and to the strong link between flow resistance and land occupation of the floodplain (Figure 1). With increasing return period, the confinement decreases and the heterogeneity in lateral and longitudinal directions of the hydraulic roughness elements (e.g. trees, houses) strongly increases. The physical processes are complex, still largely unexplored, and the assumptions linked to numerical modeling cannot be validated without field data. The Flowres ANR project (https://flowres.irstea.fr/en/) aims at improving the flood hazard assessment in floodplains, by relying on experimental data base and on one field case (floods at Besançon, France).; Selon la directive européenne sur les inondations, l'aléa hydraulique (hauteurs, vitesses) doit être évalué avec précision dans les zones à haut risque lors des crues extrêmes. Or, la prédiction des écoulements dans les plaines inondables n'est pas aisée en raison de l'absence de données de terrain et du lien étroit entre résistance à l'écoulement et occupation du sol (Figure 1). Le confinement et l'hétérogénéité des rugosités hydrauliques (comme des arbres, des maisons, ...) dans les directions latérales et longitudinales varient fortement avec l'augmentation de la période de retour de la crue. Les processus physiques sont complexes, encore largement inexplorés, et les hypothèses liées à la modélisation numérique de ces écoulements ne peuvent être validées sans données de terrain. Le projet Flowres (https://flowres.irstea.fr/en/) vise à améliorer l'évaluation de l'aléa dans les plaines inondables en s'appuyant sur les données expérimentales et sur un cas de terrain (les inondations à Besançon).
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- 2019
35. Transverse surface waves in steady uniform and non-uniform flows through an array of emergent and sligthly submerged square cylinders
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Chetibi, M., Proust, Sébastien, Benmamar, S., ECOLE NATIONALE POLYTECHNIQUE ALGER DZA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), RiverLy (UR Riverly), and Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
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Physics::Fluid Dynamics ,HHLAB ,[SDE]Environmental Sciences - Abstract
Steady uniform and non-uniform flows through an array of emergent and slightly submerged square cylinders are experimentally investigated with a specific focus on transverse seiche waves induced by vortex shedding. The study is first and foremost aimed at assessing the effect of streamwise flow non-uniformity on seiche waves. Its secondary purpose is to investigate the change in seiche magnitude, when initially emerged cylinders become slightly submerged. Thirdly and lastly, the effect of seiche waves on mean velocities and velocity fluctuations is quantified. The lock-in process between waves and vortex shedding is unaltered by flow non-uniformity and by a change from cylinder emergence to submergence. For non-uniform flows, this results in the co-existence of two differently oscillating transverse waves close to each other. Relative wave amplitude is found to be mainly influenced by relative submergence in the case of submerged cylinders, and by Froude number and oscillation mode in the case of emergent cylinders. Finally, seiche waves modify the streamwise mean velocity, when cylinders are emergent.
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- 2019
36. La modélisation hydrodynamique pour décrire les inondations et prévoir leurs conséquences
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Paquier, André, Proust, Sébastien, Faure, J.B., RiverLy (UR Riverly), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Hydrologie-Hydraulique (UR HHLY), and Irstea Publications, Migration
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[SDE] Environmental Sciences ,FLOODS ,HYDRODYNAMICS ,HYDRAULICS ,INONDATION ,HHLAB ,MODELES HYDRODYNAMIQUES ,[SDE]Environmental Sciences ,HYDRODYNAMIQUE ,FLOODING ,INONDATIONS ,HYDRAULIQUE ,HYDRODYNAMIC MODELS - Abstract
The chapter starts by describing the physical processes typical of floods, particularly, the ones that cannot be observed at low river flows. All these latter processes are linked to the various kinds of floods described above. In order to simulate these processes for flood management, a relevant spatial scale should be selected. For each kind of flood and spatial scale, one - dimensional and two - dimensional classical hydrodynamic models are explained. Limits and requirements of these latter approaches permit to introduce the recent evolutions in modelling and in available data, which permits to obtain more realistic and accurate results., Le chapitre commence par une description des phénomènes physiques propres aux inondations, en particulier, ceux qui les distinguent des écoulements ordinaires en rivière. Ces différents phénomènes sont rattachés aux différents types d'inondations qui ont été énumérés auparavant. Pour modéliser ces phénomènes en vue de la gestion des inondations, il est, entre autres, nécessaire de définir l'échelle spatiale pertinente. En fonction de cette échelle et du type d'inondation, on explique les modélisations hydrauliques classiques 1D et 2D, leurs limitations et leurs besoins ainsi que les dernières évolutions des modèles et surtout des données disponibles qui permettent d'obtenir des résultats toujours plus réalistes et parfois plus précis.
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- 2018
37. UNSTEADY FLOWS IN A COMPOUND OPEN-CHANNEL: A LABORATORY EXPERIMENT AND A 1D+ MODEL
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KADDI, YASSINE, primary, PROUST, SÉBASTIEN, additional, FAURE, JEAN-BAPTISTE, additional, and CIERCO, FRANÇOIS-XAVIER, additional
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- 2019
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38. Modélisation 2D d'écoulements à surface libre à travers de la végétation rigide : quelle stratégie appliquer pour simuler des crues extrêmes ?
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Oukacine, M., Peltier, Y., Goutal, Noémie, Proust, Sébastien, LABORATOIRE D'HYDRAULIQUE SAINT VENANT ENPC FRA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), EDF (EDF), Hydrologie-Hydraulique (UR HHLY), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), and Irstea Publications, Migration
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[SDE] Environmental Sciences ,FLOWRES ,EMERGENT ROUGHNESS ELEMENT ,HHLAB ,RIGID VEGETATION ,[SDE]Environmental Sciences ,2D MODELLING ,CYLINDER - Abstract
International audience; The simulation of open-channel flows through emergent rigid vegetation is carried out, using the open-source TELEMAC-2D system. The aim of this study is to find an optimal representation of the flow resistance caused by emergent rigid vegetation for a wide range of flow rates in absence of calibration data for the highest flows. Two strategies of flow resistance representation are compared: (1) the vegetation, in addition to the bed friction, is implicitly considered in a flow resistance coefficient; or (2) the vegetation is explicitly considered by being excluded from the computation domain. Results emphasize that the explicit representation is the more accurate solution for computing both flow depth and velocity, but field data are generally not available. The uncertainty observed on the water depth with the implicit representation is higher than for the explicit representation, but it can be reduced by using more evolved resistance coefficient.
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- 2017
39. Mixing layer and coherent structures in compound channel flows: Effects of transverse flow, velocity ratio, and vertical confinement
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Proust, Sébastien, Fernandes, Joao N., Leal, Joao B., Rivière, Nicolas, Peltier, Yann, Laboratoire de Mecanique des Fluides et d'Acoustique (LMFA), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), and EDF (EDF)-EDF (EDF)
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FLOWRES ,HHLAB ,COHERENT STRUCTURE ,TRANSVERSE CURRENTS ,QUASI-2D TURBULENCE ,MIXING LAYER ,FLOOD ,[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] ,COMPOUND CHANNEL ,FLOODPLAIN ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience; no abstract
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- 2017
40. Experimental study of flows in a converging channel followed by a prismatic channel with stairs
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Chetibi, M., Proust, Sébastien, Benmamar, S., Irstea Publications, Migration, ENP ALGER DZA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Hydrologie-Hydraulique (UR HHLY), and Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
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Physics::Fluid Dynamics ,[SDE] Environmental Sciences ,TRANSVERSE WAVE ,HHLAB ,[SDE]Environmental Sciences ,CONVERGENT TRANSITION ,STEPS ,RETURN WAVE - Abstract
International audience; Convergent hydraulic structures are found in different open-channel flow configurations, particularly in the courier of the surface spillway and in some stilling basins. In some cases, the convergent transition is followed by a prismatic part with the same slope and steps with a different slope. The work that is presented here focuses on the physical modeling of this flow configuration type under steady flow conditions. It has been performed in a laboratory flume, located in the hydraulic laboratory of the National Polytechnic School of Algiers. As far as we are concerned, there has not been any systematic scientific research for the conception of this configuration type so far. In particular, the slope change effect between the convergent transition and the stepped spillway has not been explored yet. According to the slope change and the flowrate, we are interested in the transverse wave propagation that arises at the convergent downhill and the maximum height of the transverse wave, We have measured water heights and instantaneous velocities (transverse and longitudinal profiles) by varying the flowrate from 2 to 20 l/s, the main channel slope (convergent transition and prismatic part) from 0° to 24.4° and the stairs slope from 0° to 45°.
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- 2017
41. Simulations of Experimental Data, in a Channel with a Rough Bottom and Macro-Roughness Elements, Using 2D Code (Rubar20)
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Chetibi, Meriem, primary, Benmamar, Saida, additional, and Proust, Sébastien, additional
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- 2018
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42. Prédire les écoulements dans les plaines d'inondations dont l'occupation du sol varie lors de crues extrêmes (Projet ANR FlowRes)
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Proust, Sébastien, Berni, Céline, Boudou, Martin, Chiaverini, Antoine, Dupuis, Victor, Faure, Baptiste, Paquier, André, Lang, Michel, Guillen Ludena, Sebastian, Lopez, Diego, Mignot, Emmanuel, RIVIERE, Nicolas, Chagot, Loic, Rouzes, Maxime, Moulin, Frédéric, Goutal, Nicole, Oukacine, Marina, Peltier, Yann, Ferreira, Rui M.L., Brito, Moisés, Alves, Elsa, Gymnopoulos, Miltiadis, Leal, Joao, Mathurin, Bastien, Soarez Frazao, Sandra, Bousmar, Didier, Fernandes, Joao, Eiff, Olivier, Hydrologie-Hydraulique (UR HHLY), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Laboratoire de Mecanique des Fluides et d'Acoustique (LMFA), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut de mécanique des fluides de Toulouse (IMFT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire d'Hydraulique Saint-Venant / Saint-Venant laboratory for Hydraulics (Saint-Venant), École des Ponts ParisTech (ENPC)-Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Instituto Superior Técnico, Universidade de Lisboa, Universidade Lisboa, Laboratório Nacional de Engenharia Civil [Lisboa] (LNEC), Laboratório Nacional de Engenharia Civil - LNEC, University of Agder, Université Catholique de Louvain (UCL), Service Public de Wallonie, Department of Computer Science [ETH Zürich] (D-INFK), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Karlsruher Institut für Technologie (KIT), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Instituto Superior Técnico, Universidade Técnica de Lisboa (IST), University of Agder (UIA), Université Catholique de Louvain = Catholic University of Louvain (UCL), and Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)
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RUGOSITE ,INONDATION ,flooding ,floodplains ,laboratory test ,[SDE]Environmental Sciences ,MODELE NUMERIQUE ,PLAINE D'INONDATION ,OCCUPATION DU SOL ,numerical model ,ESSAI AU LABORATOIRE ,land occupation ,roughness - Abstract
3rd European Conference on Flood Risk Management, Lyon, FRA, 17-/10/2016 - 21/10/2016; International audience; Flood hazards (flow depth and velocity) must be accurately assessed in high-risk areas during extreme flood events. However, the prediction of the very high flows is not an easy task due to the lack of field data and to the strong link between flow resistance and the land occupation of the floodplain. Confinement and inhomogeneity in lateral and longitudinal directions of hydraulic roughness strongly vary with return period T. The physical processes are complex, some still largely unexplored, and the assumptions linked to numerical modelling cannot be validated without field data. The FlowRes project (2015-2018), funded by the French National Research Agency (ANR), aims at improving the flood hazard assessment in floodplains in: 1) investigating in laboratory the hydrodynamic structure associated with extreme flood flows for various land occupations and flow discharge magnitudes; 2) assessing if the existing numerical modelling practices used for T ~ 100 years are still valid for extreme events with T > 1000 years, relying on the experimental
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- 2016
43. Gérer des inondations par des ouvrages dispersés sur le bassin versant : principes et méthodes de diagnostic d'efficacité probabiliste
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Royet, Paul, primary, Deroo, Luc, additional, Breil, Pascal, additional, Leblois, Étienne, additional, Faure, Jean-Baptiste, additional, Poulard, Chrsitine, additional, and Proust, Sébastien, additional
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- 2017
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44. Streamwise non-uniform overbank flows in compound channels
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Proust, Sébastien, Hydrologie-Hydraulique (UR HHLY), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), and Habilitation à Diriger des Recherches, Université Lyon I
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HYDRAULICS ,HHLAB ,FLOW ,NON-UNIFORM ,[SDE]Environmental Sciences ,RIVER ,FLOOD ,HDR ,HYDRAULIQUE ,COMPOUND CHANNEL ,ÉCOULEMENT ,OVERBANK FLOW ,DÉBORDEMENT - Abstract
My research works focus on the physical and numerical modeling of river floods, in the case of streamwise non-uniform overbank flows in compound open channels. These flows are characterized by longitudinal changes in flow depth and by a lateral time-averaged discharge between the main channel of the river and the adjacent floodplains. The longitudinal non-uniformity of flow is mostly caused by the changes in topography and land occupation of floodplains. Non-uniformity can also be related to the influence of the boundary conditions associated with the reach under consideration. These various sources of non-uniformity have been investigated throughout this work. The physical processes induced by flow non-uniformity have been studied in laboratory flumes. The analysis is carried out at the reach scale, but also at a smaller scale, with a three dimensional description of the mean flow and turbulent quantities, especially in the mixing layer developing at the junction between the main channel and the floodplains. The numerical modeling work is focused on the approaches 1D, 2D and 1D+ (development of a new method). In particular, we assess their ability to take into account the physical processes that are specific to non-uniforms flows, and eventually, to predict the flow depth and velocity in the floodplains. This is done for small overbank flows, but also for very high flows associated with extreme flood events.; Mes travaux de recherche portent sur la modélisation physique et numérique du débordement des rivières en régime non-uniforme. Ce régime est caractérisé par des variations longitudinales de hauteur d'eau, et par un débit d'échange latéral entre le lit mineur de la rivière et les plaines d'inondations adjacentes. La non-uniformité de l'écoulement est principalement due aux variations de topographie et d'occupation du sol des plaines d'inondation, mais également à l'influence des conditions limites du bief de rivière considéré. Ces différentes sources de non-uniformité ont été explorées tout au long de ces travaux. Les processus physiques induits par la non-uniformité de l'écoulement ont été étudiés dans des canaux de laboratoire. L'analyse est faite à l'échelle du bief, mais également à une échelle plus fine (description tridimensionnelle du champ de vitesse moyenne et des quantités turbulentes, notamment dans la couche de mélange entre lit mineur et lit majeur). Le travail de modélisation numérique porte sur les approches numériques 1D, 2D et 1D+ (développement d'une nouvelle méthode). En particulier, on évalue leurs capacités à prendre en compte les phénomènes physiques spécifiques aux écoulements non-uniformes, et in fine, à simuler hauteur et vitesse de l'écoulement en plaine d'inondation, pour des faibles débordements, comme pour des crues extrêmes.
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- 2015
45. Flow structure in compound open-channel flows in the presence of transverse currents.
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Paquier, A., Rivière, N., Proust, Sébastien, and Nikora, Vladimir
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- 2018
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46. Effect of climate change over land-falling hurricanes at the Yucatan Peninsula.
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Appendini, Christian, Barrios, Roberto, Meza-Padilla, Rafael, Secaira-Fajardo, Fernando, and Proust, Sébastien
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- 2019
47. Modélisation 1D par lit (ISM) d'un réseau hydraulique ramifié maillé. Application au contexte opérationnel de la prévision des fortes crues et des crues de dimensionnement d'ouvrages
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Kaddi, Yassine and PROUST, Sébastien
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Flood Modeling ,Modélisation 1D ,1D Hydraulic Model ,Inondations ,[SDU.STU.HY] Sciences of the Universe [physics]/Earth Sciences/Hydrology ,[SPI.MECA.MEFL] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] ,[SPI.GCIV.RISQ] Engineering Sciences [physics]/Civil Engineering/Risques - Abstract
The objective of this thesis is to operationalize an improved one-dimensional (1D+) modeling method for overflowing rivers, called Independent Sub-section Method (ISM). While classical 1D models solve the dynamic equation (Saint-Venant or Bernoulli) on the total cross-section of the overflowing river (or in a compound open-channel), the ISM solves a dynamic equation in each homogeneous subsection in terms of topography and roughness, i.e., in the main channel, the left-hand floodplain, or the right-hand floodplain of the overflowing river. In addition, the ISM explicitly models lateral mass transfer between subsections, as well as lateral momentum transfer. Prior to the thesis, this model was validated using uniform and non-uniform steady state experimental data. As a first step, the ISM was validated under transient conditions to ensure the modeling capabilities in the most typical hydrological situations of overflowing flows. For this purpose, a transient experiment was designed to acquire specific validation data. The processing methodology used was also the subject of an original work. This experiment was then modeled with the ISM and with a classical 1D model to compare the 1D+ and 1D approaches. It was concluded that the ISM reproduces the water heights better than the 1D, due to: (i) the consideration of the subsectional flow distribution in the upstream boundary conditions, (ii) the explicit modeling of lateral flow and momentum exchange between subsections. In addition, at the interface between subsections, lateral velocity and lateral flow are also well reproduced by 1D+. Thus, the hysteresis observed in the relationship between stage and lateral flow is reproduced throughout the hydrograph. In a second step, two methodological questions allowing to apply the ISM in operational conditions on a branched network are addressed. The first question seeks to reconstruct upstream boundary conditions for the ISM (1 flow per subsection) from the available data (1 single flow over the total section). It was then proposed to distribute the total upstream flow according to the same distribution as that obtained for the uniform regime calculated using the ISM equations. This distribution of the total upstream flow is compared to those given by different existing methods. The second issue concerns the modeling of confluences that were previously inaccessible to the ISM. The work carried out consisted in finding a solution to distribute the flows in the three subsections of each incoming branch on the three subsections of the outgoing branch of the confluence. An approach was then proposed to retain the flows from the outer floodplains of the inflow reaches into the floodplains of the outflow reach, and then sum the remaining flows from the inflow reaches into the main channel of the outflow reach. Although this method greatly simplifies the flow in the confluences, it provides an initial numerical implementation that is relatively easier to code. In all cases, numerical tests were performed to evaluate the impact of the simplifications made. Then, a field case was chosen to apply the ISM in operational conditions. Two situations were studied: a simple section model and a model with confluence. In both cases, the selected site has sufficiently representative floodplains and several documented floods. These configurations allowed to test the flow distribution method to build upstream boundary conditions, as well as the confluence treatment method. The modeling is performed with the Mage-8 code coupled with the ISM method (1D+), as well as with the CRUE 10 code coupled with the 1D DCM (Divided Channel Method) and the Mage-7 code coupled with the 1D Debord method. In this test case, the ISM reproduces the measured water levels better than the other models with lower maximum absolute biases than those obtained with the 1D DCM and Debord models. In the simulation with confluence, the maximum biases of Mage ISM are larger but remain within orders of magnitude generally accepted in the community. A proposal is suggested to improve the ISM simulation. In addition, ISM provides additional information not available in conventional 1D models such as the filling and emptying of floodplains. It also allows the analysis of the distribution of total flow between subsections or flow velocities per subsection, as well as the lateral exchange flow between subsections and the turbulent shear stress between subsections., L'objectif de cette thèse est de rendre opérationnelle une méthode de modélisation unidimensionnelle améliorée (1D+) des rivières débordantes, appelée Independent Sub-section Method (ISM). Alors que les modèles 1D classiques résolvent l’équation dynamique (Saint-Venant ou Bernoulli) sur la section totale de l'écoulement débordant (ou en lit composé), l’ISM résout une équation dynamique dans chaque sous-section homogène en terme de topographie et de rugosité, i.e., dans le lit mineur, le lit majeur gauche, ou le lit majeur droit de la rivière débordante. De plus, l’ISM modélise explicitement le transfert latéral de masse entre sous-sections, ainsi que le transfert latéral de quantité de mouvement. Avant la thèse, ce modèle a été validé à partir de données expérimentales en régime permanent uniforme et non-uniforme. Dans un premier temps, l'ISM a été validée en régime transitoire afin de s'assurer des capacités de modélisation dans les situations hydrologiques les plus caractéristiques des écoulements débordants. Pour ce faire, une expérience en régime transitoire a été conçue pour acquérir des données de validation spécifiques. La méthodologie de traitement utilisée a aussi fait l'objet d'un travail original. Cette expérience a été ensuite modélisée avec l'ISM et avec un modèle 1D classique pour comparer les approches 1D+ et 1D. Il a été conclu que l'ISM reproduit mieux les hauteurs d’eau que le 1D, en raison : (i) de la prise en compte de la répartition des débits par sous-section dans les conditions aux limites amont, (ii) de la modélisation explicite du débit latéral et de l’échange de quantité de mouvement entre lits. De plus, à l'interface entre sous-sections, la vitesse latérale et le débit latéral sont également bien reproduits par le 1D+. Ainsi, l’hystérésis observée dans le lien entre hauteur d’eau et débit latéral est reproduite tout au long de l’hydrogramme. Dans un second temps, deux questions méthodologiques permettant d'appliquer l'ISM en conditions opérationnelles sur un réseau ramifié sont traitées. La première question cherche à reconstruire des conditions aux limites amont pour l'ISM (1 débit par sous-section) à partir des données disponibles (1 débit unique sur la section totale). On a alors proposé de répartir le débit total amont selon la même répartition que celle qui est obtenue pour le régime uniforme calculé à l'aide des équations de l'ISM. Cette répartition du débit total amont est comparée à celles données par différentes méthodes existantes. La deuxième question concerne la modélisation des confluences jusqu’ici inaccessible à l’ISM. Le travail réalisé a consisté à trouver une solution pour répartir les débits par lits de chaque branche entrante sur les trois lits de la branche sortante de la confluence. On a alors proposé une approche qui consiste à conserver les débits des lits majeurs extérieurs des biefs entrants dans les lits majeurs du bief sortant, puis de sommer le reste des débits des biefs entrants dans le lit mineur du bief sortant. Bien que cette méthode simplifie grandement l’écoulement dans les confluences, elle permet d’avoir une première implémentation numérique relativement plus facile à coder. Dans tous les cas, des tests numériques ont cherché à évaluer l'impact des simplifications apportées. Ensuite, un cas de terrain a été choisi pour appliquer l'ISM en conditions opérationnelles. Deux situations ont été étudiées : un modèle de tronçon simple et un modèle avec confluence. Dans les deux cas, le site retenu présente des lits majeurs suffisamment représentatifs et plusieurs crues y sont documentées. Ces configurations ont permis de tester la méthode de répartition de débit pour construire des conditions limites amont, ainsi que la méthode de traitement des confluences. La modélisation est réalisée avec le code Mage-8 couplé à la méthode ISM (1D+), ainsi qu'avec le code CRUE 10 couplé à la méthode 1D DCM et le code Mage-7 couplé à la méthode 1D Debord. Sur ce cas test, l’ISM reproduit mieux les cotes mesurées que les autres modèles avec des biais absolus maximaux plus faibles que ceux obtenus avec les modèles 1D DCM et Debord. Dans la simulation avec confluence, les biais maximaux de Mage ISM sont plus importants mais restent dans des ordres de grandeurs généralement acceptés dans la communauté. Une proposition est suggérée pour améliorer la simulation de l'ISM. Par ailleurs, l'ISM permet de fournir des informations supplémentaires inaccessibles aux modèles 1D classiques comme le remplissage et la vidange des lits majeurs. Elle permet aussi d'analyser la répartition du débit total entre les lits ou les vitesses débitantes par lit, ainsi que le débit latéral d’échange entre lits et le cisaillement turbulent entre sous-sections.
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- 2021
48. Unsteady open-channel flows over rough bed with and without emergent rigid vegetation: A laboratory experiment
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Kishanjit Kumar Khatua, Jnana Ranjan Khuntia, Sébastien Proust, National Institute of Technology Rourkela, Riverly (Riverly), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and PROUST, Sébastien
- Subjects
[SDE] Environmental Sciences ,Hydrology ,13. Climate action ,[SDE]Environmental Sciences ,medicine ,[SPI.MECA.MEFL] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] ,medicine.symptom ,Laboratory experiment ,Vegetation (pathology) ,6. Clean water ,Geology ,Open-channel flow ,[SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] - Abstract
International audience; We report here a laboratory study on the effects of bed roughness and emergent rigid veg-etation on the unsteady flows associated with flash floods and extreme flood events. The flow structure of unsteady open-channel flows over rough bed with and without emergent rigid vegetation has been investigated in an 18m long and 3m wide laboratory flume. Steady uniform flows were also studied and served as reference flows. For both steady and unsteady flows, two geometries are tested: (1) uniform bed roughness (uniform dense synthetic grass modelling meadow) along the flume and (2) a uniform staggered distribu-tion of emergent wooden circular cylinders (model of rigid vegetation) set on the bed roughness. Transient flow depths are simultaneously measured at six longitudinal positions using ultra-sonic sensors. Transient velocities are measured at one longitudinal position over the water column using a side looking ADV probe to estimate depth-averaged veloci-ty. In order to compute ensemble averages of the flow parameters, 109 runs of the same hydrograph are carried out repeatedly at the flume entrance. Two consecutive runs are separated by a base flow. The ensemble averages of the measured discharge, flow depths and velocity are found to be converged after 72 runs. For the two geometries: at the peak flow of the hydrograph, the vertical profiles of mean streamwise velocity and horizontal Reynolds shear stress are comparable to the profiles obtained for steady uniform cases of same flow depth; and accelerated and decelerated velocity profiles are obtained during the rising limb and falling limb of the hydrograph, respectively. Reynolds shear stresses are also found to be higher during the rising limb than during the falling limb for a fixed flow depth. The hysteresis in the depth-averaged velocity / flow depth relationships is compa-rable in shape and size for the two geometries highlighting the weak effect of the rigid vegetation compared to the effects of un-stationarity.
- Published
- 2020
49. Emergence of Kelvin-Helmholtz instabilities in shallow mixing layers: An experimental study
- Author
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Vladimir Nikora, Sébastien Proust, C. Berni, Riverly (Riverly), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), UNIVERSITY OF ABERDEEN GBR, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), and Proust, Sébastien
- Subjects
[SDE] Environmental Sciences ,shear layer turbulence ,Materials science ,Shallow shear flows ,coherent structures ,[SPI.MECA.MEFL] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] ,Mechanics ,01 natural sciences ,010305 fluids & plasmas ,[SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] ,Physics::Fluid Dynamics ,symbols.namesake ,Helmholtz free energy ,0103 physical sciences ,[SDE]Environmental Sciences ,symbols ,010306 general physics ,Mixing (physics) - Abstract
International audience; Free-surface shallow mixing layers behind a splitter plate were studied in a flume of rectangular cross-section consisting of a bed and sidewalls made of glass. The focus is on the effects on the emergence of horizontal Kelvin-Helmholtz-type coherent structures (KHCSs) of vertical flow confinement (i.e., flow depth) and dimensionless velocity shear λ = (Ux2 − Ux1)/(Ux2+Ux1), where Ux1 and Ux2 are two flow velocities characterizing the low-speed stream and high-speed stream, respectively. Two flow depths were tested, with the λ-value at the flume entrance varying between 0.1 to 0.8, with a threshold value λt = 0.3 needed for the emergence of KHCSs in compound open-channel flows being inside this range. This paper reports new data that provide a better insight in the interplay between the constraining effect of flow depth, damping effect of three-dimensional bed-induced turbulence, and triggering effect of dimensionless shear on the formation of KHCSs.
- Published
- 2020
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